1. Technical Field
The present invention relates to a projection type display apparatus using a liquid crystal panel, and a lighting device which is used in the projection type display apparatus.
2. Related Art
In a projection type display apparatus, light which is output from a lighting device is modulated using a liquid crystal panel, and is projected from a projection optical system thereafter. Here, when an extra-high pressure mercury lamp or the like is used in a light source of the lighting device, a lot of ultraviolet range light beams are included in white light which is output from the light source, and when the ultraviolet range light is input to the liquid crystal panel, a liquid crystal material deteriorates.
On the other hand, in the projection type display apparatus, a reflection type cutoff filter, a reflection type cutoff filter of which a cut-on wavelength is a longer than that of the cutoff filter, and an absorption type cutoff filter are arranged in order between the light source and a polarizing conversion element in order to prevent the polarizing conversion element from being deteriorated due to the ultraviolet range light, and a technology of blocking out the ultraviolet range light using the cutoff filter has been suggested (refer to JP-A-2007-212733).
In the technology which is described in JPA-2007-212733, between two reflection type cutoff filters, a cut on wavelength of a cutoff filter on the liquid crystal panel side is longer than that of a cutoff filter on the light source side, and therefore, a lot of ultraviolet range light beams also reach the cutoff filter on the liquid crystal panel side. For this reason, there is a problem in that heat generation in the cutoff filter on the liquid crystal panel side influences the liquid crystal panel.